1. Field of the Invention
The present invention generally relates to the production of semen for artificial insemination in animals. More specifically, the present invention is concerned with a process which will eliminate or reduce infectious virus contamination in semen and semen free of infectious virus thereby produced.
2. Description of the Prior Art
In the artificial insemination of animals, it is well-known that the semen can potentially be contaminated with different viruses that can cause a variety of diseases. At present, there is no safe or effective procedure to eliminate viral contamination from semen even though it is known that bacterial contamination of semen can be eliminated or reduced by the addition of antibiotics. No drug presently available will similarly eliminate virus without significantly affecting the viability of the sperm. (See, e.g. Bartlett et al, "Specific Pathogen Free (SPF) Frozen Bovine Semen: A Goal?", Proc. 6th Tech. Conf. on AI and Repro. N.A.A.B., pp. 11-12 (1976); and Schultz, "When Can We Achieve Our Goal of Providing Specific Pathogen Free Bovine Semen?" U.S.A.H.A. Proc., 81:141-140 (1979)). It has also been suggested that when antibody is present as a result of immunization or previous infection in body fluids or when this antibody, if present in serum, milk or egg yolks, is added to viruses in vitro rapidly eliminates or reduces their infectivity for susceptible cells in culture or eliminates infectivity for susceptible animals. (See, Bellanti, Immunology II, W. B. Saunders Co., Philadelphia, PA. (1978). Myrvik and Weisen, Fundamentals of Immunology, Lea & Febiger, Philadelphia, PA (1984)).
Viral contamination of semen has serious implications for the cattle industry since one infected bull shedding virus in his semen could potentially infect cattle regionally, nationally or even internationally thereby leading to quarantine and/or destruction of valuable livestock as a result of infection and/or disease. Artificial insemination and the procedures used for the performance of artificial insemination serve as a means by which viral contaminated semen could be collected, preserved, stored and disseminated to the cattle population without the knowledge of the parties involved.
It is apparent that because of the potential danger that viral contaminated semen presents to the cattle industry, there is a distinct need for a method which will eliminate or reduce viral contamination of semen thus eliminating the problem for both the artificial insemination industry and the cattle producer. Although the need has been apparent, this need went unanswered until the present invention.
It has been proposed in the art that semen can be preserved for a period of time as evidenced by U.S. Pat. Nos. 3,472,735 and 4,329,337. However, as the reader will appreciate from an inspection of those U.S. patents, no solution to the elimination of viral contaminated semen has been suggested. Thus although such proposals may permit storage of semen, the semen which is stored may be contaminated with various viruses. (e.g., Bartlett et al, "Specific Pathogen (SPF) Frozen Bovine Semen: A Goal?", Proc. 6th Tech. Conf. on AI and Repro. N.A.A.B., pp. 11-12 (1976).